WASHINGTON _ In 1995, the racially polarized reaction to the O.J. Simpson verdict presaged the enormous gathering on the National Mall for the Million Man March. Ten years later, Hurricane Katrina and its stark reminder of the distinctly different conditions many black people endure have set the stage for the Millions More Movement and its commemorative march on the mall Oct. 15.

O.J., Katrina and the continuing history of black mass gatherings are reminders of how time and circumstance have produced a collective identity, forged by crisis, that still sets black America apart. More than anything else, the gatherings in 1995 and again this year are a way to recognize that nation within a nation.

“It’s a coming together of who we are, affirming blackness and black culture, and affirming that African-Americans have survived in this society, despite a long history of oppression and hardship,” said Robert L. Allen, professor of African-American studies at the University of California at Berkeley. “It’s about building community and bringing together a very broad spectrum of the African-American community.”

Who would have imagined in 1963, when Martin Luther King’s March on Washington brought 250,000 people to the mall to demand an end to legal segregation, that three decades later a march called by Minister Louis Farrakhan of the black nationalist Nation of Islam would draw a far larger crowd? That it would be composed almost exclusively of African-American men around an agenda of introspection and atonement?

The 1995 event was by far the largest African-American public gathering in history. Now, another decade gone, black Americans again assemble on the mall to express the unity of a people who, as Farrakhan puts it, are “slipping further behind.”

A strong collective identity is central to the African-American psyche and shows no signs of dimming with time, said University of Chicago political scientist Michael Dawson, an expert on black political opinion. No group in America is as politically cohesive.

“One of the themes throughout African-American history, going back to before the Civil War, is many African-Americans viewing themselves as a nation, or a nationality, within the borders of the United States,” Dawson said.

And why not?

Schools are more segregated than a decade ago, according to the Harvard Civil Rights Project. The rise of the black middle class has been accompanied by the rise of the black suburb. “Ghetto” has a throwback air about it, but well describes deeply poor black neighborhoods like the Lower Ninth Ward in New Orleans, where black English rules and African-influenced first names mark that this is not Jacob-and-Emily America. Prison is a rite of passage for many black men.

The enormous gap between black and white wealth has grown, as blacks actually lost wealth between 1996 and 2002, according to the Pew Hispanic Center.

“We’re talking about nearly 40 million (black) people in this country. Forty million people in a land who don’t have serious power or economics. It’s a crime. It’s obscene,” said Haki Madhubuti, the Chicago poet, publisher and educator who with Maulana Karenga edited the commemorative volume, “Million Man March/Day of Absence.”

Blacks get their information from the usual sources, but also from black media, at the barbershop, in church, or, as in a recent case, at a shelter for Katrina evacuees in Charlotte, N.C., where Farrakhan said he had “heard from a very reliable source” that a levee in a New Orleans “may have been blown up, so that the water would destroy the black part of town, and where the whites lived, it would be dry.” Reckless, paranoid demagoguery, or reasonable suspicion, given all that’s come before?

Ten years ago it was the image of blacks reacting with delight to the acquittal of O.J. Simpson that shocked many whites. How, they wondered, could so many blacks watch the same events unfold and react so differently to the outcome?

Now comes Katrina.

According to a survey conducted by the Pew Research Center for the People and the Press (1,000 adults, including an oversample of African-Americans, interviewed Sept. 6-7), two-thirds of blacks, but only 17 percent of whites, thought the government would have responded faster if the hurricane’s victims had been white. For 71 percent of blacks, but only 32 percent of whites, Katrina proved that racial inequality was still a major problem.

“The racism that I saw in New Orleans, the do-nothing attitude in the treatment of those who were there, it takes me back to the early days of racism,” said Joseph Dulin, principal of an Ann Arbor, Mich., alternative high school. “People who say it wasn’t anything racist, well, you have to have been a victim to feel these things, to know these things.”

According to the Pew survey, while a stunning 22 percent of whites said they had a close friend or relative directly affected by Katrina, an astonishing 43 percent of blacks said they had that firsthand connection.

“Katrina is to black people what 9/11 was to white people,” said Raymond Winbush, director of the Institute for Urban Research at Morgan State University in Baltimore, who likens the Oct. 15 march to a national organizational meeting in the wake of a great tragedy. “This is going to be another watershed moment in black American history.”Te

The Million Man March inspired countless acts of community building by those who went home determined to do more for their people. Dulin returned to Ann Arbor and founded National African American Parent Involvement Day. Richard Shorter of West Orange, N.J., started the Boys to Men mentorship program at St. Mark’s AME Church in East Orange.

But then and now, some were disappointed that the 1995 event asked more of black men than of America.

John Bracey Jr. was a 22-year-old organizer with the Congress of Racial Equality in Chicago when he went to the 1963 March on Washington. He is now a scholar of black nationalism at the University of Massachusetts at Amherst.

“Why would you go all that way to Washington to blame everything on yourself?” Bracey recalled asking students who made the trek in 1995. Of this month’s event, he said, “Someone is supposed to nail 10 theses on the White House door.”

In fact, the Millions More Movement has a 10-point agenda under the headings of unity, spiritual values, education, economic development, political power, reparations, the prison-industrial complex, health, artistic/cultural development and peace.

Farrakhan, though, has proved a mercurial leader. In the years since the Million Man March he has pursued alliances with the fringe white political leader Lyndon LaRouche, with Sun Myung Moon and his conservative Unification Church, and with the Libyan dictator Moammar Gadhafi.

Still, his position outside the mainstream, as a man uncompromised by having to make accommodations with white America, may help him rally black Americans under the banner of racial solidarity.

“What we’re talking about with modern black nationalism is a feeling or spirit or group identity, that because of skin color, because of background, black people are undervalued or oppressed,” said William Van Deburg, a professor of Afro-American studies at the University of Wisconsin in Madison and the author of “Modern Black Nationalism.” This march, like the last one, is about “affirming blackness.”

And beyond that?

“What’s become more obvious to me is that we’re not a monolithic group of people,” said Shorter, the real estate appraiser from West Orange, N.J. “I’m tired of Jesse Jackson and Al Sharpton and the Congressional Black Caucus. I ain’t into federal programs.

“What’s that gotten us in New Orleans and Newark and East Orange and Milwaukee?”